North Korea says leader Kim Jong Un observed the first test-firings of missiles from a recently launched destroyer and called for speeding efforts to boost his navy’s nuclear attack capabilities.

North Korean leader Kim Jong Un called for accelerating the nuclear weapon capability of the Korean People’s Army Navy as he saw the first day of weapons firing trials for newly launched multipurpose destroyer Choe Hyon (51) reported state media Korean Central News Agency (KCNA) on Wednesday.

North Korean officials blamed increased tensions with the U.S. and cooperative military drills with South Korea and Japan as reasons for the testing.